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<pre class="textdiagram" id="fig18">
             +-----------+
             |           |
             |   Client  |
             |           |
             +-----------+
             |    REQ    |
             \-----+-----/
                   |
             R1, R2, R3, R4
                   |
     +-------------+-------------+
     |             |             |
  R1, R4           R2            R3
     |             |             |
     v             v             v
/---------\   /---------\   /---------\
|   REP   |   |   REP   |   |   REP   |
+---------+   +---------+   +---------+
|         |   |         |   |         |
| Service |   | Service |   | Service |
|    A    |   |    B    |   |    C    |
|         |   |         |   |         |
+---------+   +---------+   +---------+
</pre>
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